The present invention relates generally to a hermetic compressor assembly and, more particularly, to a direct suction compressor assembly having a crankcase mounted within a sealed housing, wherein suction gas is delivered directly to the crankcase from the suction line and compressed refrigerant is discharged into the sealed housing.
In general, prior art of hermetic compressor assemblies comprise a hermetically sealed housing having a compressor mechanism mounted therein. The compressor mechanism may include a crankcase or a cylinder block defining a compression chamber therein in which gaseous refrigerant is compressed and subsequently discharged. Typically, and especially in the case of a compressor having a pressurized housing, suction gas returning from a refrigeration system is provided to the compression chamber by means of a conduit extending from outside the housing to the compression chamber within the crankcase. This configuration is commonly referred to as a direct suction compressor. In such a compressor, it is known to introduce suction tubing through the housing and into a suction inlet opening in the crankcase or cylinder block that is in communication with the compression chamber. The portion of the tubing external of the housing may comprise part of a suction accumulator or may constitute a fitting to which a suction line of a refrigeration system may be attached.
U.S. Pat. No. 4,470,772 discloses a direct suction scotch yoke compressor wherein the pump portion of the compressor is disposed in an upper chamber and the motor is disposed in a lower chamber, the two being separated by a wall of the crankcase. The lower chamber in which the motor is disposed is at suction pressure due to vents 98 and passageways 94 which lead from the suction chamber to the lower motor chamber. A disadvantage to this design is that heat from the motor is imparted to the suction gas, thereby reducing efficiency. Furthermore, the discharge tube for the high pressure discharge gas is located in the upper chamber, thereby isolating the motor from discharge gas and necessitating that the motor be cooled solely by the oil.